There is already known such a vacuum operated brake booster which is provided with tubes for the introduction of fixing screws, at the same time holding the master cylinder in a dismountable manner separately on the brake booster.
Such a brake booster is described in the document EP2058195, of which FIG. 2C which is included here as FIG. 5 shows the introduction tube of a vacuum operated brake booster according to the prior art; the reference numerals used in FIG. 2C are included here by way of a reminder.
In FIG. 5, the tube 222 for introduction of the screw is fixed to the base 213 by the fold 240 thereof forming an abutment surface. The cover 215 is fixed near the other end of the introduction tube by means of a washer 230 which presses on an axial abutment which is in the form of a fold and which is produced at this location of the introduction tube 222. Beyond the cover 215, the introduction tube comprises an outer threaded zone which receives a sleeve which increases the diameter and which extends through the leg 203 of the master cylinder. The sleeve 232 has an outer thread for receiving a nut 234 which fixes the leg 203 to the sleeve.
The brake booster is fixed by means of the screw 220 whose head 221 of reduced diameter presses against the end 232 of the sleeve. The threaded portion 236 extends through the wall of the engine compartment in order to be fixed by a nut which is not illustrated.